II. Mechanism

  1. Macrolide that inhibits RNA Polymerase, and in turn Protein synthesis, leading to Bacterial cell death
  2. Narrow spectrum antibiotic (C. difficile, Staphylococcus, Enterococcus)
    1. Does not affect Gram Negative Bacteria including normal bowel flora
  3. Minimal systemic absorption when taken orally
    1. As with oral Vancomycin, oral Fidaxomicin primarily stays in the Gastrointestinal Tract

III. Indications

  1. Clostridioides difficile (Clostridium difficile)
    1. Considered first-line as of 2021 (preferred over Vancomycin due to lower recurrence rates)

IV. Contraindications

  1. Macrolide allergy
    1. Unclear if allergy to Macrolides applies due to minimal systemic absorption

V. Dosing: Clostridioides difficile (Clostridium difficile)

  1. First Episode
    1. Fidaxomicin 200 mg orally twice daily for 10 days (up to 14 days if delayed treatment response)
  2. Recurrence
    1. Start: 200 mg orally twice daily for 10 days (or 200 mg orally twice daily for 5 days)
    2. Next: 200 mg orally once every other day for 20 days

VI. Adverse Effects

  1. Fever (13% of children and teens)
  2. Nausea (11% of adults)

VII. Pharmacokinetics

  1. No renal or hepatic dosing adjustment needed

VIII. Efficacy

  1. Clostridioides difficile (Clostridium difficile)
    1. High efficacy (90% cure rate, similar to Vancomycin)
    2. Lower C. difficile recurrence rates than with Vancomycin

IX. Safety

  1. Unknown effects in pregnancy but limited systemic absorption

X. Cost

  1. Very expensive as of 2022 ($250/dose or $3000 to $4300 for a 10 day course in Clostridium difficile)

XI. References

  1. LoVecchio (2022) Crit Dec Emerg Med 36(9): 32

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Cost: Medications

dificid (on 1/6/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
DIFICID 200 MG TABLET $214.53 each